This invention relates to a face mask suitable for use during diving or the like.
In the face mask used during diving or the like, it is well known to length-adjustably couple a head strap to a lens frame of the face mask by means of buckles. Each of the buckles usually comprises a first support member extending rearward from the associated lateral end of the lens frame, a second support member pivotally supported by the first support member and a spring biasing the second support member to swing so that the head strap may be held between the first and second support members. The first and second support members are placed upon each other so that the first support member may lie immediately adjacent the face mask and the second support member may lie outside the first support member. The head strap is guided and folded back by the first support member. A locking tooth formed on the second support member is adapted to be engaged with any one of plural locking teeth formed on the head strap under a biasing effect of the spring thereby to prevent the head strap from moving in its slackening direction.
The face mask of prior art uses, for example, a coil spring as the spring. In this case, the spring is set between the first and second support members so that the spring may be oriented in in-and-out direction of the face mask. The coil spring used for this purpose usually has been too small in its diameter as well as in its length to ensure that the spring can be adequately compressed and firmly inserted between the first and second support members. In addition, it has been further difficult to disassemble the spring once incorporated into the buckle for the purpose of inspection and exchange.
An object of this invention is to provide a face mask for diving provided with buckles facilitating a spring to be incorporated into or removed from each of the buckles.
In accordance with this invention, there is provided a face mask for diving comprising front lenses, a skirt extending rearward from the front lenses, a lens frame securing a front end of the skirt to a peripheral edge of the lenses, a head strap and buckles for length-adjustably coupling longitudinal opposite ends of the head strap to respective lateral ends of the lens frame.
This invention further comprises the head strap having a length direction, a width direction and a thickness direction orthogonal to the length and width directions. Each of the buckles includes a first support member and a second support member cooperating with each other to hold the head strap therebetween, the first support member extending rearward from the lateral end of the lens frame and having a guide pin extending in the width direction of the head strap so that the head strap is folded back around the guide pin, the second support member being formed separately of the lens frame and pivotally supported by the first support member around a pivot pin, the second support member having a first arm extending rearward from the pivot pin and formed with a second locking tooth adapted to be selectively engaged with one of first locking teeth formed on a section of the head strap folded back around the guide pin. Each of the buckles further includes a spring extending in the width direction of the head strap and adapted to be inserted from the front or the lateral side of the face mask into a space defined between a distal end of a second arm of the second support member extending forward from the pivot pin and a distal end of the first support member opposed to the distal end of the second support member so that the spring is compressed and elastically deformed between the distal ends to bias the second support member to swing until one of the first locking teeth comes in engagement with the second locking tooth thereby to prevent the head strap from moving in a slackening direction thereof.
In the face mask according to this invention, the buckle comprises the first support member and the second support member placed upon and pivotally supported by the first support member. The spring biasing the second support member to swing can be incorporated into the buckle merely by inserting it between the first and second support members from the front or the lateral side of the face mask. In this way, both assembly and disassembly of the buckle is facilitated and, in consequence, production, maintenance and inspection of the face mask are correspondingly facilitated. The face mask arranged so that the spring can be inserted inward radially of the face mask into the space defined between the first and second support members advantageously eliminates an anxiety that the buckles might become bulky at the mask wearer""s temples and a fluid-resistance of the face mask might increase.